API Documentation

Classes

Board

godash.Board(dimensions = 19, ...moves)

Representation of a board position.

Extends Immutable.Record.

Constructor Arguments

• dimensions (number) - Size of the board, defaulted to 19.
• ...moves (Move) - Moves to be placed on the board.

Properties

• dimensions (number) - Size of the board.
• moves (Immutable.Map) - Stones present on this board. Coordinate keys with either BLACK or WHITE values.

Examples

var board = Board();

board.toString();
// => Board { "dimensions": 19, "moves": Map {} }

var smallBoard = Board(5, Move(Coordinate(2, 2), BLACK));

smallBoard.toString();
// => Board { "dimensions": 5, "moves": Map { {"x":2,"y":2}: "black" } }

var smallBoard = Board(5, Move(Coordinate(2, 2), BLACK));

smallBoard.toString();
// => Board { "dimensions": 5, "moves": Map { {"x":2,"y":2}: "black" } }

Coordinate

godash.Coordinate(x, y)

A zero-based tuple representing a single location on a Go board.

Extends Immutable.Record.

Constructor Arguments

• x (number) - Location on the X-axis.
• y (number) - Location on the Y-axis.

Properties

• x (number) - Location on the X-axis.
• y (number) - Location on the Y-axis.

Examples

var tengen = Coordinate(9, 9);

tengen.toString();
// => Coordinate { "x": 9, "y": 9 }

tengen.x;
// => 9

Move

godash.Move(coordinate, color)

Representation of a move, composed of a Coordinate and a color.

Extends Immutable.Record.

Constructor Arguments

• coordinate (Coordinate) - Location of the move.
• color (string) - BLACK, WHITE, or EMPTY.

Properties

• coordinate (Coordinate) - Location of the move.
• color (string) - BLACK, WHITE, or EMPTY.

Examples

var tengen = Move(Coordinate(9, 9), BLACK);

Constants

BLACK

godash.BLACK

The color black.

EMPTY

godash.EMPTY

An empty space.

TENGEN_13

godash.TENGEN_13

Center point on a 13x13 board.

TENGEN_19

godash.TENGEN_19

Center point on a 19x19 board.

TENGEN_9

godash.TENGEN_9

Center point on a 9x9 board.

WHITE

godash.WHITE

The color white.

Board utilities

addMove

godash.addMove(board, move)

Function to add a move onto a board while respecting the rules. Since no sequence information is available, this function does not respect ko. Use followupKo if you want to do ko-related things.

Arguments

• board (Board) - Board from which to add the move.

• move (Move) - Move or location of the move.

Returns

Board - New board with the move played.

Examples

var atari = Board(3,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(1, 1), WHITE),
);

toAsciiBoard(atari);
// => +O+
//    OXO
//    +++

var killed = addMove(
    atari,
    Move(Coordinate(2, 1), BLACK)
);

toAsciiBoard(killed);
// => +O+
//    O+O
//    +O+

---

constructBoard

godash.constructBoard(coordinates, board, startColor)

Constructs a board for an array of coordinates. This function iteratively calls addMove while alternating colors.

Arguments

• coordinates (Array) - Ordered Coordinate moves.

• board (Board) - Optional starting board. Empty 19x19, if omitted.

• startColor (string) - Optional starting color, defaulted to BLACK.

Returns

Board - New board constructed from the coordinates.

Examples

var tigersMouth = Board(3,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
);

toAsciiBoard(tigersMouth);
// => +O+
//    O+O
//    +++

var selfAtari = Coordinate(1, 1);
var killingMove = Coordinate(2, 1);

var ponnuki = constructBoard(
    [selfAtari, killingMove],
    tigersMouth,
    WHITE
);

toAsciiBoard(ponnuki);
// => +O+
//    O+O
//    +O+

---

difference

godash.difference(board1, board2)

Finds the moves on the first board that are not on the second board.

Arguments

• board1 (Board) - First board.

• board2 (Board) - Board with moves to subtract from first board.

Returns

Set - Set containing pairs of Coordinate and color remaining in the difference.

Examples

var atari = Board(3,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(1, 1), WHITE),
);

toAsciiBoard(atari);
// => +O+
//    OXO
//    +++

var captured = difference(
    atari, addMove(atari, Move(Coordinate(2, 1), BLACK))
);

captured.toString();
// 'Set { List [ Coordinate { "x": 1, "y": 1 }, "white" ] }'

---

followupKo

godash.followupKo(board, move)

Determines move that would be illegal under the ko rule

Arguments

• board (Board) - Starting board.

• move (Move) - Intended Move.

Returns

Coordinate - Position of illegal followup or null if none exists.

Examples

const koPosition = Board(4,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(1, 1), WHITE),
    Move(Coordinate(2, 0), WHITE),
    Move(Coordinate(2, 2), WHITE),
    Move(Coordinate(3, 1), WHITE),
);

toAsciiBoard(koPosition);
// => +O++
//    OXO+
//    X+X+
//    +X++

const koStart = Coordinate(2, 1);

followupKo(koPosition, koStart, BLACK).toString();
// => 'Coordinate { "x": 1, "y": 1 }'

---

fromA1Coordinate

godash.fromA1Coordinate(raw)

Construct a Coordinate from an A1-style coordinate string.

An A1-style coordinate is given in the form A1 to T19 with I omitted to avoid confusion with J.

This function accepts raw coordinates from A-Z.

Arguments

• raw (string) - A1-style coordinate to convert.

Returns

Coordinate - Coordinate representation of A1-style input.

Examples

---

group

godash.group(board, coordinate)

Finds the set of coordinates which identifies the fully connected group for the given location.

Arguments

• board (Board) - Board to inspect.

• coordinate (Coordinate) - Location to inspect.

Returns

Set - Containing Coordinate for the members of the group.

Examples

var board = Board(3,
    Move(Coordinate(1, 0), WHITE),
    Move(Coordinate(0, 2), WHITE),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(2, 2), BLACK),
    Move(Coordinate(2, 1), BLACK),
);

toAsciiBoard(board);
// => ++X
//    X+O
//    +OO

group(board, Coordinate(2, 1)).toString();
// => Set {
//      Coordinate { "x": 2, "y": 1 },
//      Coordinate { "x": 2, "y": 2 },
//      Coordinate { "x": 1, "y": 2 }
//    }

---

handicapBoard

godash.handicapBoard(size, handicap)

Creates a Board with the correct number of handicap stones placed. Only standard board sizes (9, 13, 19) are allowed.

Arguments

• size (number) - Size of board, must be 9, 13, or 19.

• handicap (number) - Number of handicaps, must be 0-9.

Returns

Board - New board with handicaps placed.

Examples

var board = handicapBoard(9, 4);

toAsciiBoard(board);
// => +++++++++
//    +++++++++
//    ++O+++O++
//    +++++++++
//    +++++++++
//    +++++++++
//    ++O+++O++
//    +++++++++
//    +++++++++

---

isLegalBlackMove

godash.isLegalBlackMove(board, coordinate)

Partial application of isLegalMove, fixing the color to BLACK.

Arguments

• board (Board) - Board to inspect.

• coordinate (Coordinate) - Location to check.

Returns

boolean - Whether the move is legal.

Examples

---

isLegalMove

godash.isLegalMove(board, move)

Determine whether the coordinate-color combination provided is a legal move for the board. Ko is not considered. Use followupKo if you want to do ko-related things.

Arguments

• board (Board) - Board to inspect.

• move (Move) - Move to check.

Returns

boolean - Whether the move is legal.

Examples

var ponnuki = Board(3,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(2, 1), BLACK),
);

toAsciiBoard(ponnuki);
// => +O+
//    O+O
//    +O+

isLegalMove(ponnuki, Move(Coordinate(1, 1), BLACK))
// => true

isLegalMove(ponnuki, Move(Coordinate(1, 1), WHITE))
// => false

---

isLegalWhiteMove

godash.isLegalWhiteMove(board, coordinate)

Partial application of isLegalMove, fixing the color to WHITE.

Arguments

• board (Board) - Board to inspect.

• coordinate (Coordinate) - Location to check.

Returns

boolean - Whether the move is legal.

Examples

---

liberties

godash.liberties(board, coordinate)

Finds the set of all liberties for the given coordinate. If the coordinate is part of a group, the set of liberties are the liberties for that group.

Arguments

• board (Board) - Board to inspect.

• coordinate (Coordinate) - Coordinate to inspect.

Returns

Set - Containing Coordinate members for the liberties of the passed coordinate.

Examples

var board = Board(3, Move(Coordinate(1, 1), BLACK));
var collectedLiberties = liberties(board, Coordinate(1, 1));

Immutable.Set.of(
    Coordinate(1, 0),
    Coordinate(0, 1),
    Coordinate(1, 2),
    Coordinate(2, 1)
).equals(collectedLiberties);
// => true

---

libertyCount

godash.libertyCount(board, coordinate)

Counts the liberties for the given coordinate. If the coordinate is part of a group, liberties for the entire group is counted.

Arguments

• board (Board) - Board to inspect.

• coordinate (Coordinate) - Coordinate to inspect.

Returns

number - Count of liberties for the coordinate on the board.

Examples

var board = Board(3, Coordinate(1, 1), BLACK);

libertyCount(board, Coordinate(1, 1)) === 4;
// => true

---

oppositeColor

godash.oppositeColor(color)

Toggles the passed color.

Arguments

• color (string) - godash.BLACK or godash.WHITE

Returns

string - Color opposite of the one provided.

Examples

oppositeColor(BLACK) === WHITE
// => true

oppositeColor(WHITE) === BLACK
// => true

---

placeStone

godash.placeStone(board, coordinate, color, force)

Places a stone on the board, ignoring the rules of Go.

Arguments

• board (Board) - Board to add stone.

• coordinate (Coordinate) - Location to add stone.

• color (string) - Stone color - BLACK or WHITE.

• force (boolean) - Optionally allow placement over existing stones.

Returns

Board - New board with the move placed.

Examples

var ponnuki = Board(3,
    Move(Coordinate(1, 0), BLACK),
    Move(Coordinate(0, 1), BLACK),
    Move(Coordinate(1, 2), BLACK),
    Move(Coordinate(2, 1), BLACK),
);

toAsciiBoard(ponnuki);
// => +O+
//    O+O
//    +O+

toAsciiBoard(
    placeStone(ponnuki, Coordinate(1, 1), WHITE)
);
// => +O+
//    OXO
//    +O+

---

placeStones

godash.placeStones(board, coordinates, color, force)

Places a set of stones onto the board, ignoring the rules of Go.

Arguments

• board (Board) - Board to add stones.

• coordinates (Array) - Stones to place.

• color (string) - Stone color - BLACK or WHITE.

• force (boolean) - Optionally allow placement over existing stones.

Returns

Board - New board with the moves placed.

Examples

var board = Board(3, Coordinate(1, 1), WHITE);

toAsciiBoard(board);
// => +++
//    +X+
//    +++

toAsciiBoard(
    placeStones(board, [
        Coordinate(1, 0),
        Coordinate(0, 1),
        Coordinate(1, 2),
        Coordinate(2, 1)
    ], BLACK)
);
// => +O+
//    OXO
//    +O+

---

removeStone

godash.removeStone(board, coordinate)

Make a given coordinate empty on the board.

Arguments

• board (Board) - Board from which to remove the stone.

• coordinate (Coordinate) - Location of the stone.

Returns

Board - New board with the stone removed.

Examples

var board = Board(3, Move(Coordinate(1, 1), WHITE));

toAsciiBoard(board);
// => +++
//    +X+
//    +++

toAsciiBoard(
    removeStone(board, Coordinate(1, 1))
);
// => +++
//    +++
//    +++

---

removeStones

godash.removeStones(board, coordinates)

Makes several coordinates empty on the board.

Arguments

• board (Board) - Board from which to remove the stone.

• coordinates (Coordinate) - Location of the stones.

Returns

Board - New board with the stones removed.

Examples

var board = Board(3,
    Move(Coordinate(1, 0), WHITE),
    Move(Coordinate(1, 1), WHITE),
    Move(Coordinate(1, 2), BLACK),
);

toAsciiBoard(board);
// => +++
//    XXO
//    +++

toAsciiBoard(
    removeStones(board, [
        Coordinate(1, 1),
        Coordinate(1, 2)
    ])
);
// => +++
//    X++
//    +++

---

toA1Coordinate

godash.toA1Coordinate(coordinate)

Construct an A1-style coordinate string from a Coordinate.

An A1-style coordinate is given in the form A1 to T19 with I omitted to avoid confusion with J.

This function accepts coordinates in the range 0-24, mapping from A-Z.

Arguments

• coordinate (Coordinate) - Coordinate to convert.

Returns

string - String A1-style coordinate.

Examples

---

toAsciiBoard

godash.toAsciiBoard(board)

Constructs an ASCII representation of the board.

Arguments

• board (Board) - Board to represent.

Returns

string - ASCII representation of the board.

Examples

var board = Board(3,
    Coordinate(1, 0), BLACK,
    Coordinate(0, 1), BLACK,
    Coordinate(1, 2), BLACK,
    Coordinate(1, 1), WHITE
);

toAsciiBoard(board);
// => +O+
//    OXO
//    +++

---

toString

godash.toString(board, overrides)

Constructs a string representation of the board.

Arguments

• board (Board) - Board to represent.

• overrides (Object) - Overrides print characters, indexed by color constants.

Returns

string - String representation of the board.

Examples

var board = Board(3,
    Coordinate(1, 0), BLACK,
    Coordinate(0, 1), BLACK,
    Coordinate(1, 2), BLACK,
    Coordinate(1, 1), WHITE
);

toString(board, {[BLACK]: 'B', [WHITE]: 'W"});
// => +B+
//    BWB
//    +++

---

SGF utilities

coordinateToSgfPoint

godash.coordinateToSgfPoint(coordinate)

Converts a Coordinate to an SGF Point in the form of a Javascript String.

Arguments

• coordinate (Coordinate) - Coordinate to convert.

Returns

string - 2-character string representing an SGF Point

Examples

coordinateToSgfPoint(Coordinate(0, 0))
// => "aa"

---

sgfPointToCoordinate

godash.sgfPointToCoordinate(sgfPoint)

Converts an SGF Point to a Coordinate.

Arguments

• sgfPoint (string) - 2-character string representing an SGF Point

Returns

Coordinate - Corresponding Coordinate.

Examples

sgfPointToCoordinate('hi').toString();
// => Coordinate { "x": 7, "y": 8 }

---

sgfToJS

godash.sgfToJS(sgf)

Converts a raw SGF string into a plain Javascript array. Note that unlike Board, the results of this function is a mutable object.

Arguments

• sgf (string) - Raw SGF string to be parsed.

Returns

Array - Unpacked SGF in plain Javascript objects.

Examples

var rawSgf = `(
    ;FF[4]GM[1]SZ[19];B[aa];W[bb]
        (;B[cc];W[dd];B[ad];W[bd])
        (;B[hh];W[hg]C[what a move!])
        (;B[gg];W[gh];B[hh]
            (;W[hg];B[kk])
            (;W[kl])
        )
)`;

sgfToJS(rawSgf);
// => [
//        {FF: '4', GM: '1', SZ: '19'}, {B: 'aa'}, {W: 'bb'},
//        [
//            [{B: 'cc'}, {W: 'dd'}, {B: 'ad'}, {W: 'bd'}],
//            [{B: 'hh'}, {W: 'hg', C: 'what a move!'}],
//            [
//                {B: 'gg'}, {W: 'gh'}, {B: 'hh'},
//                [
//                    [{W: 'hg'}, {B: 'kk'}],
//                    [{W: 'kl'}]
//                ]
//            ]
//        ]
//    ];

---